This invention relates to loudspeaker systems for converting an electrical signal, originating at an audio amplifier, to an audio signal to be radiated within a listening area, and in particular to such loudspeaker systems which receive their signal from the audio amplifier without any direct connection by wire.
It is known to transmit information wirelessly by use of infrared light. Very small amounts of information, for example, are transmitted by hand-held remote control devices for televisions, compact disk players and other electronic apparatus. Basically this information is merely comprised of control information, such as changing the channel to which a television is tuned, changing the track which a compact disk player is to play, or adjusting the volume of the device. These control devices are not intended to send continuous signals over a long period of time, but rather short bursts of the control information. Supplying power to the receivers of this information is generally no problem, since the receiving apparatus requires substantially more power for its other components, and so is generally connected to a substantial source of power such as line voltage.
Further, it is known to transmit and receive audio signals use of a carrier in the infrared range. In a brochure entitled "Wireless Communication With Infrared Light", Sennheiser Electronic Corporation, of New York, described a monophonic system wherein audio information was transmitted from a transmitter to a headphone-type receiver for use in listening to the audio information. This system, as mentioned, was monophonic, however, and thus not suitable for use with stereophonic audio information. The demand for a system which can accommodate stereophonic audio information is already great, and it is increasing with the advent of AM stereo radio broadcasting, and particularly with stereo sound for television.
Moreover, with respect to loudspeakers, the wires necessary to transmit the audio signal to the loudspeakers have made the installation of such systems more difficult and less aesthetically pleasing since stereo systems were first introduced. Another problem with transmission of the audio signal by wire is the possibility that the source of the audio signal could overpower a loudspeaker, possibly even damaging the components of the loudspeaker. A demand exists for a loudspeaker system which is capable of providing excellent sound quality without the necessity or possible risk presented by wires transmitting the audio signal to the loudspeaker system.
This invention relates to improvements over the systems described above and to solutions to the problems raised thereby.